The present invention relates to a floating hydroponic biofiltration device, and more particularly such a device adapted to be used in a body of oxygenated water containing plant-eating fish.
Biofiltration systems for ponds and aquaria having water and fish are well known. Indeed, the broad concept of floats to support plants is disclosed in U.S. Pat. No. 4,037,360 and in U.S. Pat. No. 5,799,440 for terrestrial plants as well as U.S. Pat. No. 5,337,516 for wetland plants. However, the '360 Patent requires the plants to float in a tank of nutrient solution rather than the natural water of a pond or aquaria. Further, other floating biofiltration systems require the use of soil, such as U.S. Pat. No. 5,618,428 and U.S. Pat. No. 5,799,440, so that the plant is not grown hydroponically (that is, through the use of water, without soil).
It is also known to use nitrogen-converting bacteria in a water tank to convert the ammonia-containing waste from the fish (via nitrites) into the useful nitrates (required by the plant). Typically, the ammonia waste produced by the fish increases in concentration over time until the bacteria is not able to convert it all into useful nitrates; at that point the water is poisoned and should actually be changed. See, for example, U.S. Pat. No. 5,746,921.
The present invention is aimed primarily for use in outdoor ponds containing Koi (large oriental carp), although it also finds utility in various aquaria and in connection with other plant-eating fish. Although the device is specifically designed to protect the plant material from being eaten by the Koi who tend to be omnivorous (at times even eating their young) and would readily devour any plants they can reach.
Accordingly, it is the object of the present invention to provide a floating hydroponic biofiltration device for use in a body of oxygenated water containing plant-eating fish.
Another object is to provide such a device which is suitable for use in outdoor ponds containing Koi.
A further object is to provide such a device which provides a substrate for the growth of nitrogen-converting bacteria which convert the ammonia of fish waste to nitrates useful to plants.
It is a further object to provide such a device which is simple and economical to manufacture, use and maintain.